Temperature controlling method for ceramic furnaces or kilns



May 10, 1932. I 5, T-r5 1,857,702

TEMPERATURE CONTROLLING METHOD FOR CERAMIC FURNACES OR KILNS Filed June 19, 1930 ELECTRIC FURN WARE CHAMBE ELECTRIC HEATING UNIT OF KILN MULTIPLE OUT T 0F DRAF MULTIPLE INLET OF AUXILIARY AIR GAS 0R LIQUID FUEL FIRED FURHACE SOLID FUEL TO BE CONV ED T0 GASEOUS FUEL BEFQR NTERIIIG THIS WARE CHAMBER.

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3% m m m" 9 WITH 5UFFICIENT AIR CO ETE COMBUSTION DH LY OMFITICIILLY CONTROLLED MULTIPLE OUTLET OF DRAFT Patented May 10, 1932 UNITED STATES PATENT OFFICE ARTHUR S. WATTS, F COLUMBUS, OHIO TEMPERATURE CONTROLLING METHOD FOR CERAMIC FURNACES 0R KILNS Application filed June 19, 1930. Serial No. 462,272.

In the drawings: pending on the composition of the article and Figure 1 is a diagrammatic vertical transthe temperature and time necessary to develop verse section of an electrically heated kiln emthe desired surface characteristics. bodying my invention. I have found that if such articles are heat- Figure2 is a similar view of a gas or liquid ed to a temperature slightly below that necfuel fired kiln. essary for the development of the desired sur- The reference numeral 3 designates a kiln face characteristics and maintained at this having a draft outlet, a draft inlet at near the temperature for a proper period of time, and bottom of the kiln and a draft inlet 5 near if the temperature of the article is then raised the top of the kiln. An electric heating unit (5 abruptly to a temperature slightly higher is located in the kiln, said unit being conthan that normally employed in the firing of trolled by the rheostat 7 having contacts 8 such wares and maintained at this temperaand a contact arm or switch 9 pivotally ture for a very brief period of time, followed mounted. The draft inlet 5 is provided with by an abrupt moderate temperature drop, $5 a damper 10 connected to a. pivoted arm 11 the product will possess a superior surface m which in turn is pivotally connected to the and superior mechanical strength. switch 9 by a link 12, so that simultaneous To accomplish this special treatment, a action of damper 10 and switch 9 is assured. suitable kiln or furnace is necessary in which The arrows indicate the direction of the the desired temperatures can be developed draft into and out of the kiln. and provided with suitable mechanism by In Figure 2 my invention is shown emwhich the required abrupt temperature bodied in a gas or liquid fuel fired furnace changes can be accomplished. or kiln in which I provide a draft inlet 13 and If electrically heated, these abrupt tema draft outlet 14:. Above'the inlet 13 I properature changes may be accomplished by 25 vide an auxiliary air inlet 15. A damper 16 providing a rheostat control combined with common to the inlets 13 and 15 simultaneousa system of ventilation so that when an ly controls these inlets, said damper being abrupt temperature increase is desired the moved by a suitably controlled arm 17 The flow of current can be increased and simulouter end of the inlet 13 is flared and in this taneously the ventilation be decreased, thus flared end is positioned a nozzle like element reducing the amount of heat lost by draft. 18 in the outer end portion of which is posi- \Vhen an abrupt temperature drop is desired, tioned a tube 19. It will be noted that the the flow of current is reduced and the ventilawalls of the inlet 13, nozzle 18, and tube 19 are tion increased, thus abruptly reducing the spaced from each other. heat introduced and by ventilation, remov- In the firing of special porcelains which are mg a large amount of the heat present. o of the self-glazing type, the interior of the Either or both of these systems may be emarticle is usually fired toa degree of vitrificaployed as the case may demand, tion approaching fusion in order to secure the If the kiln or furnace is heated by means desired degree of surface density and brilof solid, liquid, or gaseous fuel the abrupt 'liancy. This is accomplished in the present temperature increase is accomplished by sistate of the art by heating the article to a multaneous increase of fuel supply and repredetermined temperature and maintaining duction of excess air admitted to the furnace. this temperature until the surface displays the If an abrupt temperature decrease is desired, desired maturity." This results in a certain the fuel supply is decreased and the excess loss of detail and a degree of distortion, deair admitted to the furnace or kiln is inceramic wares for the purpose of producing creased. At all times, however, the amount of air admitted must be sufficient to give complete combustion, unless a reducing atmosphere is desired.

The kiln or furnace indicated in the description is of the periodic type in which the ware is placed after forming or after a low temperature biscuit firing to remove carbonaceous matter present, and where it remains stationary throughout the various heating and cooling treatments. The essential features of my invention are (1) The control of abrupt temperature changes by means of the ventilation ofthe chamber in which the ware is located, the ventilation being decreased for the development of higher temperatures and increased for lowering of temperature. The heat generation remains constant.

(2) The simultaneous increase of electric current and decrease of ventilation to increase temperature and the simultaneous decrease of electric current and increase of ventilation to decrease temperature.

Thesimultaneous increase of fuel and decreaseof'ventilation to increased temperature' and the simultaneous decrease of fuel 'andincrease of ventilation to decrease temperat-ure.

While I have shown apparatus for the purpose ofill-ustrating my invention it will, of

, coursefbe understood that my invention-is not limited to such apparatus, the invention being basic in principle as relatedin the appended claims. 7

What I claim is:

1. The method of controlling the tempera- ='ture in a kiln for firing porcelains andsi-milar ceramic products for the purpose of pro- :ducing desired surface characteristics ofthe product, which consists in heating the -kiln' chamber in which the ware is located, and a controlling the heating action by abrupt temperature changes by means of the ventilation of the chamber in-Which the ware is located, clecreasing the ventilation for the development of higher temperatures and increasing the ventilation for lowering of temperatures.

' 2. The method of controlling the temperature in=a kiln for firing porcelains and similar desiredsurface characteristics of the prodnot, which consists in heating theware, and simultaneously increasing the supply of heat and-decreasing the rate of ventilation to increase the temperature, and simultaneously decreasing the supply of heat and increasing the rate of ventilation to decrease temperature.

3. The method of controlling the temperature in a kiln for firing porcelains and similar ceramic products for the purpose of producdevelopment of desired surface characteristics, which consists in firing the article to a degree of vitrification :approaching fusion by: heating the article to-a temperature close .toibntibelow surface fusing temperature and maintaining suchtemperature for a predetermined period of time, then abruptly raising V the temperature to a degreeabove thesurface fusing point and maintaining the same until. 11116 .desi-red :surface t characteristics are prothe temduced, and then abruptly reducin perature to a degree below'thesur point.

5. The method'o'f "furnace-or "kiln firing porcelains of the self-glazing type forthe development of desiredsurface characteristics, which consists in firing the article to-a de ree ofvitrification approaching fusion in ce fusing a ur-nace or kiin havingaconstant'flow of. temperature 'niodifying current of air by heating the article to atemperature close to but below surface fusing temperature and 1 maintaining such temperature for 1a predeterrnined; period of time, then abruptly raising the temperature to :a degree above the-surface fusing point and maintaining the sameuuntil thedesireds1-1rface= characteristics are p1 0- duce'd,and then increasing the 'air: flowv and abruptly reducing the temperature toa'degree below the 1 surface fusing point.

6. The method of 'furnace-or vkilnifiring porcelains of theself glazingtype for the development of desired surface characteristics,

which consists in firing the article in a t furnace or kiln=i n the presence ofa constantly "flowin current ofalr to a'temperature. close "to but-dielow surface fusing temperature and maintaining such temperature for a predetermined period o'ftime; then reducing the flow of air and-abruptlyraising the temperature of the kiln to-a degree above the surface: fusi-ng temperature and maintaining such temperature until the desiredsurface chat-adoristics are 'produced,-andthen increasing the air flow and abruptly reducing-the temperature to a degree below the. surface fusing point.

"7LThe' method of furnace or kiln f 'fin'mg porcelains of t-he self-glazing type in a kiln v or furnace "for the development of desired surfacecharacteristics, which consists in: in-

troducing fuel with n current of-air together with an auxiliary --tem perature modafying current of airinto a the kiln and: heating the article-tea temperature close to but below surface fusing temperature for a given periodof time, then decreasing the auxiliary current of air and increasing the supply of fuel to abruptly raise the temperature to a degree above surface fusing temperature for a short period and until the desired surface characteristics are produced, and then reducing the supply of fuel and increasing the flow of the auxiliary current of air to abruptly reduce the temperature to a degree below the surface fusing point.

In testimony whereof I aflix my signature.

ARTHUR S. WATTS. 

